KR20090060418A - Ultraviolet radiation protective effect evaluation method and device - Google Patents

Abstract

An ultraviolet radiation protective effect evaluation method comprising a first step of measuring the variation with time of a spectral transmission spectrum of a sample under measurement by applying light including ultraviolet radiation from a light source for a predetermined light application time, a second step of correcting the spectral transmission spectrum of the sample under measurement according to the variation with time on the basis of the measurement results obtained at the first step, and a third step of calculating the final in vitro SPF estimation of the sample under measurement by using the correction results obtained at the second step.

Description

Evaluation method and evaluation device of UV protection effect {ULTRAVIOLET RADIATION PROTECTIVE EFFECT EVALUATION METHOD AND DEVICE}

The present invention relates to an evaluation method and an evaluation device for the ultraviolet protective effect.

SPF (Sun Protection Factor) value is used as a measure which shows the ultraviolet protection effect of the cosmetics (so-called sun care goods) for preventing sunburn by an ultraviolet-ray. This SPF value protects skin from sunburn by ultraviolet rays and does not use suncare product for the amount of ultraviolet rays necessary to cause faint redness when suncare product is used as index which shows effect to prevent sunburn In this case, it is defined by the value divided by the amount of ultraviolet light needed to cause faint redness. For example, using a sun care cosmetic with an SPF value of 10 means that tanning is the same as bare skin when exposed to 10 times of ultraviolet rays when sunburned with bare skin. For the measurement of the SPF value, artificial light (solar simulator) that is very close to the sunlight is used instead of sunlight which may have a different value depending on the season and the place. The measurement method is based on irradiating a certain amount of ultraviolet rays to the unapplied skin and the right skin, respectively, and to investigate whether erythema is caused the next day.

By using the SPF value measured in accordance with the above-described method, an objective evaluation of the ultraviolet protection effect of the sun care product becomes possible. However, the above-described method requires a great deal of cost and days because the cooperation of many specific skin type subjects is indispensable. Therefore, for example, for the evaluation of the ultraviolet protective effect of a product in the development stage, for example, in vitro, the calculation of the in vitro SPF prediction value with high correlation with the in vivo SPF value obtained by the above-mentioned method is simple. Development of the method has been expected.

Conventionally, as a method for evaluating the ultraviolet protective effect by in vitro prediction, a dilute solution method in which a sample diluted with an organic solvent is placed in a quartz cell and the absorbance or transmittance of the ultraviolet light is measured, and a sample is used. The thin film method etc. which form on a quartz plate as a film film of uniform thickness, and measure the absorbance or transmittance | permeability of the ultraviolet-ray are known. Although such a conventional method is meaningful in order to grasp | ascertain the characteristics, such as absorption maximum wavelength and a defensive wavelength range of a ultraviolet absorber, SPF value could not be estimated. This is because the evaluation method of these ultraviolet protective effects differs greatly from the method of measuring in vivo SPF value. In addition, the bioreaction represented by the SPF value has a wavelength dependence of ultraviolet rays and ranges from ultraviolet wavelengths that are easy to cause erythema reactions to ultraviolet wavelengths that are less likely to cause erythema reactions. It was thought that there was.

In the non-patent document 1, the sample is apply | coated on the medical tape as a skin replacement film, and the spectral transmission spectrum of a sample is measured about the above two problems. This measurement result was calculated by the Diffey & Robson equation, and the SPF value was calculated. This Diffey & Robson formula has succeeded in solving the above-described problems because the Diffey & Robson equation has been adapted to use the erythema coefficient disclosed in Non-Patent Document 2 for the wavelength dependence of erythema reaction as a human bioreaction.

However, because the in vivo SPF value has all kinds of factors such as individual difference, site difference, age difference, sex difference, and skin type difference, the SPF value is accurately predicted only by one example of erythema coefficient. It is actually a very difficult thing to do.

Therefore, not only the erythema coefficient is employed, but also the relational expression between a large number of samples having a known in vivo SPF value and the spectral transmission spectrum to derive a mathematical expression for obtaining a statistically high correlation. Also in a sample, the evaluation method which can predict in vitro SPF value is proposed (for example, refer patent document 1). By this evaluation method, the in vitro SPF prediction value was obtained with high accuracy, and the factor of the nonuniformity resulting from individual difference, site difference, age difference, sex difference, and skin type difference was also solved.

Non Patent Literature 1: Journal of the Society of Cosmetic Chemists (1989) 40:33, 127-133

Non Patent Literature 2: CIE Journal (1987) 6: 1, 17-22

Patent Document 1: Japanese Patent No. 337832

[Initiation of invention]

[Problem to Solve Invention]

However, the method for evaluating the ultraviolet protective effect disclosed in Patent Document 1 has a problem that, although the precision can be predicted up to about 30 SPF values, accurate prediction cannot be performed for samples having SPF values of 30 or more. . In recent years, products with an SPF value of 50 or more are the mainstream, and products having a higher SPF value are expected to be introduced in the future.

In recent years, much knowledge has been found about the phenomenon of photodegradation caused by ultraviolet light of ultraviolet absorbers. Therefore, also in the calculation method of the in vitro SPF prediction value, it is thought that correct estimation of the substantial reduction of SPF value by reproducing the light irradiation conditions similar to the measurement conditions of an in vivo SPF value is essential for accurate SPF value prediction.

The present invention has been devised in view of the above-mentioned point, and reflects the light deterioration phenomenon of a sample by irradiation light, and also shows a high correlation with an in vivo value even in a sample having a high SPF value. An object of the present invention is to provide a method for evaluating the ultraviolet protective effect and an evaluation apparatus for the ultraviolet protective effect using the method.

[Means for solving the problem]

In order to achieve the above object, the present invention is characterized by taking each of the means described below.

 The evaluation method of the ultraviolet protective effect of the present invention is a first step of measuring the change over time of the spectral transmission spectrum of the measurement sample by light irradiation of a light source including ultraviolet light by a predetermined light irradiation time; A second step of performing correction according to the chronological change of the spectroscopic transmission spectrum of the measurement sample based on the measurement result obtained by the first step, and the final result of the measurement sample using the correction result obtained by the second step. have a third step of calculating in vitro SPF estimates.

In addition, the apparatus for evaluating the ultraviolet protective effect of the present invention includes time-dependent change measuring means for measuring the time-dependent change in the spectral transmission spectrum of the measurement sample by light irradiation of a light source including ultraviolet light by a predetermined light irradiation time; The final in vitro SPF of the measurement sample using the correction means for correcting the change according to the spectral transmission spectrum of the measurement sample over time based on the measurement result obtained by the measurement means, and the correction result obtained by the correction means. SPF prediction value calculation means for calculating a prediction value.

[Effects of the Invention]

According to the present invention, a method for evaluating the ultraviolet protective effect by in vitro measurement, which reflects a light deterioration phenomenon of a sample by irradiation light and shows a high correlation with an in vivo SPF value even in a sample having a high SPF value, and It is possible to provide an apparatus for evaluating the ultraviolet protective effect using this method.

1 is a diagram showing an example of a schematic configuration of an apparatus for evaluating the ultraviolet protective effect of the present embodiment.

2 is a diagram showing an example of a functional configuration of an apparatus for evaluating the ultraviolet protective effect of the present embodiment.

3 is a diagram showing a correlation between a known in vivo SPF value and a predicted in vitro SPF value in a standard sample of the present embodiment.

4 is a flowchart of a method for evaluating the ultraviolet protective effect of the present embodiment.

[Description of the code]

10: evaluation device of ultraviolet protection effect

11: light source

12: filter

13: optical fiber

14: investigation port

15: sample

16: skin replacement membrane

17 spectrometer

18: photodetector

19: computer

21: input means

22: output means

23: accumulation means

24: spectral transmission spectrum measuring means

25: means for setting the irradiation time

26: measuring means of change over time

27: correction means

28: SPF prediction value calculation means

29 control means

Best Mode for Carrying Out the Invention

Next, the best embodiment of this invention is described with drawing.

The method for evaluating the ultraviolet protective effect of the present embodiment and the apparatus for evaluating the ultraviolet protective effect using the method include, for example, spectroscopic transmission of a measurement sample by light irradiation of a light source containing ultraviolet light at a predetermined light irradiation time. This measurement consists of a first step of measuring the change over time of the spectrum, a second step of correcting according to the change of the obtained spectral transmission spectrum over time, and a third step of calculating the final in vitro SPF prediction value of the measurement sample. .

Further, the first step includes, for example, measuring the spectral transmission spectrum of the measurement sample with ultraviolet rays of 290 to 400 nm every 1 nm, and determining the light irradiation time of the present measurement described later from the obtained spectral transmission spectrum. You may make a preliminary measurement. This method and apparatus will be described below.

[Schematic Configuration Example of Evaluation Device]

1 is a diagram showing an example of a schematic configuration of an apparatus for evaluating the ultraviolet protective effect of the present embodiment.

Referring to FIG. 1, the apparatus 10 for evaluating the ultraviolet protective effect is, roughly, a light source 11, a filter 12, an optical fiber 13, an irradiation port 14, and a skin substitute film 16. ), A spectrometer 17, a photodetector 18, and a computer 19. This ultraviolet protective effect evaluation apparatus 10 is an apparatus for applying the evaluation method of the ultraviolet protective effect mentioned later to a measurement sample.

The light source 11 is preferably used as a xenon lamp in this embodiment, but is not limited thereto. In addition, the light source 11 is connected with the computer 19 mentioned later, and the on / off of the light source 11 is controlled by the computer 19.

The filter 12 is in the vicinity of the traveling direction of the light from the light source 11, and a predetermined amount of light, for example, UVB or UVA of 290 to 400 nm, is emitted from the light source 11. It is set as an ultraviolet region. This means reproducing and irradiating a light source at an in vivo SPF measurement site. The WG320 filter and the UG11 filter (both manufactured by SCHOTT) are suitably used as the filter 12 as UVB and UVA ultraviolet rays having the wavelength of 290 to 400 nm described above, but the present invention is not limited thereto. Etc., an appropriate filter is used.

The optical fiber 13 is near the advancing direction of the light from the filter 12. Ultraviolet light transmitted through the filter 12 is led to the irradiation port 14.

The above-mentioned ultraviolet ray is irradiated from the irradiation port 14, the irradiation port 14 and the photodetector 18 are fixed at predetermined intervals, and the skin substitute membrane 16 to which the sample 15 is applied in a predetermined amount and method. ) Is fixed at a fixed distance from the irradiation port 14. In the order in which the light proceeds, the irradiation port 14, the sample 15, the skin replacement membrane 16, the spectrometer 17, and the photodetector 18 are arranged in this order. In addition, the arrangement up to the skin replacement membrane 16 is in accordance with the in vivo SPF measurement method specified by the International Sun Protection Factor Test Method (INTERNATIONAL SUN PROTECTION FACTOR (SPF) TEST METHOD, February 2003).

The skin replacement membrane 16 is coated with the measurement sample 15, and replaces the skin of the living body in the in vivo SPF measurement, and is preferably made of a material which does not absorb ultraviolet rays of 290 to 400 nm. Patent Document 1 discloses a method of using a medical tape as a skin replacement membrane. In the present embodiment, a PMMA (poly methacrylic acid methyl) resin plate (Plexiglas ^™ , manufactured by Schonberg GmbH & Co. KG) is suitably used, but is not limited thereto.

The photodetector 18 spectra the light in the range of 290 to 400 nm with the spectrometer 17 at intervals of 1 nm, converts the respective intensities into voltages, A / D converts them, and outputs them to the computer 19. In the apparatus 10 for evaluating the ultraviolet protective effect, the photodetector 18 detects the light transmitted through the measurement sample 15 and the skin substitute membrane 16.

The computer 19 inputs the spectroscopic intensity for every 1 nm from the photodetector 18, performs the process mentioned later, and calculates the light irradiation time and final in vitro SPF prediction value in this measurement. In addition, the computer 19 controls on / off of the light source 11 as mentioned above.

In addition, the computer 19 receives the data from the photodetector 18, processes the data so that the contents are easy to be understood by the user, displays the result on the screen, records the result on a recording sheet, or outputs the result. Can be stored in a storage medium. In addition, the computer 19 can use a general-purpose personal computer etc., for example, and can perform each function in the evaluation apparatus 10 mentioned above by the instruction | indication of a user by an input means etc., and the like.

(Functional configuration example of evaluation device)

2 is a diagram showing an example of a functional configuration of the ultraviolet protective effect evaluation device of the present embodiment.

Referring to FIG. 2, the apparatus 10 for evaluating the ultraviolet protective effect is, roughly, an input means 21, an output means 22, an accumulation means 23, a spectral transmission spectrum measurement means 24, And the irradiation time setting means 25, the time-dependent change measuring means 26, the correction means 27, the SPF predicted value calculating means 28, and the control means 29.

The input means 21 is provided in the computer 19, for example, and accepts input of various data such as an instruction to start evaluation from a user or the like and outputs a measurement result by the output means 22. In addition, the input means 21 consists of a pointing device, such as a keyboard and a mouse, for example.

In addition, the output means 22 is provided in the computer 19, for example, and displays and outputs the content input by the input means 21, the content executed based on the input content, and the like. In addition, the output means 22 consists of a display, a speaker, etc. In addition, the output means 22 may have a function such as a printer. In that case, a simple measurement result or a calculation result may be printed on a print medium such as paper and provided to a user.

Incidentally, the accumulating means 23 is provided in, for example, the computer 19, and the results measured by the spectral transmission spectrum measuring means 24, the irradiation time set by the irradiation time setting means 25, and the time-dependent change. As a result of the measurement by the measuring means 26, various data such as the correction information obtained by the correction means 27 and the result calculated by the SPF predicted value calculating means 28 are accumulated.

In addition, the spectral transmission spectrum measuring means 24 measures the spectral transmission spectrum of the measurement sample 15 every 1 nm with ultraviolet rays of 290 to 400 nm by the photodetector 18 or the like. That is, the spectral transmission spectrum measuring means 24 performs a preliminary measurement for determining the light irradiation time in the present measurement. Moreover, the irradiation time setting means 25 sets the light irradiation time based on the spectral transmission spectrum obtained by the preliminary measurement in the above-mentioned spectral transmission spectrum measuring means 24 as a function of the computer 19. In addition, the detail of preliminary measurement is mentioned later.

In addition, the time-dependent change measuring means 26, as a function of the computer 19, detects the time-dependent change in the spectral transmission spectrum of the measurement sample 15 by light irradiation by the light irradiation time set by the irradiation time setting means 26. Measure In addition, the time-dependent change measuring unit 26 measures the time-dependent change due to the light deterioration of the spectral transmission spectrum in the measurement sample 15. Thereby, the in vitro SPF prediction value which reflected the light deterioration phenomenon of the sample by irradiation light can be calculated.

Further, the correction means 27 performs correction according to the chronological change of the spectral transmission spectrum of the measurement sample 15 based on the measurement result obtained by the chronological change measuring means 26 as a function of the computer 19. The SPF predicted value calculating means 28 calculates the final in vitro SPF predicted value of the measurement sample using the correction result obtained by the correction means 27 as a function of the computer 19.

In addition, the control means 30 controls each component part of the evaluation apparatus 10 as a function of the computer 19. Specifically, for example, based on an instruction from the input means 21 by a user or the like, the measurement of the spectral transmission spectrum, the setting of the irradiation time, the measurement of light degradation, the correction according to the change of the spectral transmission spectrum over time, the in vitro SPF Control of the calculation of the predicted value is performed. The control means 29 also controls the light source 11 on / off as a function of the computer 19. In addition, the detail of this measurement is mentioned later.

(Preliminary measurement)

Here, as will be described later, during the preliminary measurement, the photodetector 18 measures, for example, the spectral transmission spectrum in the ultraviolet region of 290 to 400 nm at a predetermined wavelength interval. Predetermined wavelength intervals include, for example, every 1 nm and every 5 nm, but are not particularly limited in the present invention. Therefore, in the following description, it measures every 1 nm as an example. In addition, in order to measure every 1 nm, although the photodetector 18 and the spectrometer 17 which matched the sensitivity characteristic to this wavelength range are required, it is not specifically limited. However, in order to measure the spectral transmission spectrum every 1 nm, the wavelength resolution of the spectrometer 17 needs to be 1 nm or less.

In the evaluation apparatus and evaluation method of the ultraviolet protective effect, in order to measure the spectral transmission spectrum of the sample, the higher the SPF value of the sample, the higher the ultraviolet absorption effect by the sample, and as a result, the amount of transmitted light decreases. Therefore, in order to accurately predict the SPF value even in a sample having a high SPF value of more than 50, a light detection organ having excellent detection sensitivity of weak light is required. As the photodetector, a photodiode array, a CCD, and the like have been generally used. However, with the progress of the weak light detection technology in recent years, the photomultiplier tube which raises the detection sensitivity is increasing in many cases. It is theoretically clear that the detection sensitivity is higher than conventional photodiode arrays and CCDs, but it is necessary to select the material of the photoelectric surface of the photomultiplier tube according to the wavelength region of the light to be detected. In this embodiment, especially by using the photomultiplier tube which is excellent in a sensitivity characteristic in the ultraviolet region of 290-400 nm, it can measure even a sample with a high SPF value.

(Determination of preliminary measurement and light irradiation time)

In this embodiment, the preliminary measurement which measures the spectral transmission spectrum of a measurement sample is performed before this measurement. The light irradiation time in this measurement is determined from the spectral transmission spectrum of the sample obtained by this preliminary measurement. The method of determining this light irradiation time starts from calculating a provisional in vivo SPF prediction value based on the measurement result of the standard sample whose in vivo SPF value is known.

Spectrum transmission spectra are measured for a plurality of standard samples having an in vivo SPF value, and a multivariate analysis is performed on the correlation between the spectrum and the known in vivo SPF value from the transmitted light intensity for each wavelength. It is close to the in vivo SPF value based on a calibration curve composed of a point group plotted in relation between the numerical value obtained from the multivariate analysis and the in vivo SPF value, and the spectral transmission spectrum of the measurement sample. This is an interpretation method to obtain a provisional in vitro SPF estimate.

Moreover, the multivariate analysis of this embodiment is characterized by using the PLS (Partial Least Squares) regression method which is a well-known analysis method. The commonly used regression analysis is a method for regression analysis using all the parameters used for the analysis, and can be used in principle for the analysis of data including many factors. However, when there are many explanatory variables compared to the objective variable, an appropriate regression equation cannot be obtained because excessive fitting is performed. On the other hand, PLS regression used as the present embodiment is one method of constructing a predictive model when there are a large number of explanatory variables. PLS regression can be a very useful tool when prediction is the final goal and there is no real need to limit the number of factors to measure. This is the case, for example, when using the data of the same spectral spectrum.

3 is a diagram showing a correlation between an in vivo SPF value and an in vitro SPF predicted value in a standard sample.

Referring to FIG. 3, the SPF value is predicted by the above-described PLS regression method in a standard sample having an in vivo SPF value. The abscissa represents known in vivo SPF values, and the ordinate represents in vitro SPF estimates, respectively.

In addition, the in vitro SPF prediction value shown in the vertical axis of FIG. 3 is the result predicted by taking this preliminary measurement and this measurement as will be described later, and considering the light degradation phenomenon of the sample, and the correlation (R ² = 0.9745) is shown. As shown, the predictive value of in vitro SPF is high. Therefore, when the spectral transmission spectrum of the measurement sample is obtained by preliminary measurement, the SPF value of the measurement sample can be grasped to some extent as a potential in vitro SPF prediction value.

The light irradiation time of the measurement sample is reproduced in vivo SPF measurement conditions performed using an actual living body, so that the higher the temporary in vitro SPF prediction value, the longer the light irradiation time is, so as to be proportional to the in vitro SPF prediction value. Is set. Therefore, it calculates based on 1MED (Minimul Erythema Dose) in the measurement site of in vivo SPF value. Here, 1 MED means the amount of ultraviolet light required to cause a minimum amount of erythema at the site of examination of the subject at the measurement site of the in vivo SPF value.

In the ultraviolet lamp (solar simulator) used in the in vivo SPF measurement site, since the light quantity and spectral distribution of the light source are standardized, 1 MED is mainly expressed in units of time. This is confirmed in the in-vivo SPF measurement site in the state of a sample free application in a test | inspection site | part.

As described above, there are factors of deviations such as individual differences in humans, area differences, age differences, sex differences, and skin type differences, but in the present embodiment, 1 MED is 90 seconds (1.5 minutes) from 5 seconds (0.083 minutes). Assume that it is in the range of. From the assumptions, the light irradiation time in the present measurement of the present embodiment is less than the provisional in vitro SPF predicted value of 0.08 (minutes) and less than the provisional in vitro SPF predicted value of 1.50 (minutes). In view of the reproducibility of data and the like, in the present embodiment, 1 MED is preferably in the range of 10 seconds to 60 seconds, more preferably in the range of 20 seconds to 50 seconds. When the light irradiation time is calculated by this conversion, when the tentative in vitro SPF predicted value by a preliminary measurement is 50, and 1MED is 30 second (0.5 minute), 50 * 0.5 = 25 minute light irradiation will be performed.

The calculation of the light irradiation time described above is performed by the computer 19. In addition, in this measurement mentioned later, the computer 19 controls the light source 11 so that it may become predetermined light irradiation time.

(Correction due to this measurement and light deterioration)

As the measurement, 290-400 nm ultraviolet-ray is irradiated to a measurement sample continuously with the light irradiation time computed from the result of the preliminary measurement mentioned above. At this time, the change in the spectral transmission spectrum of the measurement sample is measured, a correction process is performed according to the change of the light degradation of the measurement sample, and the final in vitro SPF prediction value is calculated.

Here, the light deterioration phenomenon of the measurement sample is that the organic ultraviolet absorber is irradiated with light to cause isomerization and the like, so that the original ultraviolet light absorbing ability is lowered. That is, it means that the SPF value of the measurement sample is lowered due to the light degradation phenomenon (see, for example, Photo degradation of Sunscreen Chemicals: Solvent Consideration, Cosmetics & Toiletries (1990) 105: 41-44).

Since this light deterioration phenomenon is continuously irradiated with light even at the measurement site of an in vivo SPF value, it is thought that it occurs also in the sample on a living skin. In this evaluation system, it can confirm as a phenomenon which the change of the transmission spectrum of the sample accompanying light irradiation, ie, the amount of transmitted light increases.

The purpose of reproducing the light deterioration phenomenon of a sample is to measure the time change of the spectral transmission spectrum under continuous light irradiation conditions, and to lower the light deterioration from a preliminary in vitro SPF prediction value that does not reflect the light deterioration obtained by preliminary measurement. Considering a significant amount, the high level of final in vitro SPF estimates are calculated.

The detection of the chronological change of the spectroscopic transmission spectrum of the measurement sample in this measurement controls the light irradiation time obtained from the above-described preliminary measurement in units of seconds, and also the spectral transmission spectrum data at any time during this light irradiation time. This is accomplished by making it available for acquisition.

Specifically, in the processing by the computer 19, the condition of the light irradiation time can be set in units of seconds, such as several minutes and several seconds. The change in the spectral spectrum over time during the light irradiation time can be obtained at any time interval, such as every one minute or a time interval in which the irradiation time is equally divided into ten times. Preferably, for a predetermined light irradiation time, it is time-divided evenly, and then six or more places (including at the start of light irradiation with a time of zero), more preferably 11 or more spots To get the data. The more the spectral data therebetween, the more the optical degradation behavior of the sample can be grasped in detail, so that the accuracy of prediction can be improved.

At this time, in order to accurately grasp the light degradation phenomenon of the measurement sample of the light irradiation time, the measurement sample and the whole device should not move. Acquiring, as spectral data, time-varying behavior at the same fixed position is important for enhancing the accuracy of prediction.

From the above-described detection result of the spectral transmission spectrum of the measurement sample in the present measurement, a correction process in accordance with the change in the light deterioration of the measurement sample is performed. This correction process is achieved by predicting the in vitro SPF value from the time average spectrum of the spectral transmission spectrum of the sample in the ultraviolet region of 290 to 400 nm.

As described in the above preliminary measurement, once the spectral transmission spectrum of the measurement sample is determined, the in vitro SPF prediction value can be determined to some extent. In other words, after grasping the time-varying behavior of the spectral transmission spectrum due to the light deterioration of the measurement sample in this measurement, it is necessary to determine which spectral transmission spectrum is used to determine the in vitro SPF prediction value of the measurement sample. It is very important in doing.

By adopting the time zero, ie, the data of the spectral transmission spectrum at the start of light irradiation, the same value as the preliminary in vitro SPF prediction value in the preliminary measurement can be obtained. However, since this value does not reflect the light deterioration phenomenon of the measurement sample by continuous light irradiation, it is considered that a higher value is expected than the SPF value to be originally predicted. If the data of the spectral transmission spectrum of the latest time immediately before the end of the light irradiation time in this measurement is employed, the change is sufficiently completed by light deterioration. That is, since it is the spectral data after receiving excessive light irradiation conditions, it is thought that the SPF value of a low value compared with the SPF value of the original measurement sample is predicted.

From this, it is preferable to calculate the total transmitted light amount and then predict the in vitro SPF value in the same way as the skin exposes with time by the time integration of the spectral transmission spectrum in order to reflect the change in time originally. Do.

However, in view of the complexity of the calculation process and the like, in this embodiment, a calculation method called a time average spectrum is introduced for the data of the spectral transmission spectrum whose time changes. By calculating the in vitro SPF estimate using this time-averaged spectra, a method of obtaining the final in vitro SPF estimate highly correlated with the in vivo SPF value can be constructed.

The time average spectrum shown here averages the spectral transmission intensity for each wavelength from all the data from the spectrum data at the start of light irradiation to the last spectrum data at the light irradiation time acquired at any number of times.

The final in vitro SPF predictive value specifically measures spectroscopic transmission spectra for a plurality of standard samples of which the above-described in vivo SPF values are known, and the correlation between the spectrum and the known in vivo SPF value is determined for each wavelength. From the transmitted light intensity, the analytical curve derived by performing the analysis by the PLS regression method and the spectral transmission spectrum obtained by this measurement are computed from the result correct | amended by the time average spectrum.

By introducing the above calculation method, it is possible to predict the final in vitro SPF value from the measurement sample susceptible to light degradation to the measurement sample susceptible to light degradation by the same calculation method.

(Flow of evaluation method of UV protection effect)

4 is a flowchart of a method for evaluating the ultraviolet protective effect of the present embodiment.

The evaluation method of the above-described ultraviolet protective effect is summarized in order. Referring to Fig. 4 (a), it is a flow of preliminary measurement performed before the present measurement.

In the ultraviolet region of 290 to 400 nm, the spectral transmission spectrum of the sample is measured every 1 nm (S101).

A provisional in vitro SPF prediction value of the measured sample is calculated from the spectroscopic transmission spectrum using a calibration curve obtained by multivariate regression analysis of the correlation between the spectral transmission spectrum of the standard sample having an in vivo SPF value and the in vivo SPF value (S102). ).

The irradiation time is determined in the range of [A] × 0.08 (min) or more and less than [A] × 1.50 (min) with respect to the provisional in vitro SPF predicted value [A] (S103).

Referring to FIG. 4 (b), this is the flow of the measurement performed following the preliminary measurement.

During the time determined in S103, light is continuously irradiated onto the measurement sample to acquire spectroscopic spectral data every arbitrary time (S151).

A time-averaging process is performed on the obtained spectral transmission spectra for each elapsed time to calculate a time-average spectrum in which light deterioration of the measurement sample is corrected (S152).

Using the obtained time average spectrum and the calibration curve obtained in S102, the final in vitro SPF prediction value is calculated (S153).

Here, although the above-mentioned embodiment demonstrates the process which performs preliminary measurement before this measurement, for example, when there is the history of evaluating the same sample in this measuring system in the past, the similar result which is measured even if there is no measurement results is carried out. When it is easy to predict from a prescription example (for example, when SPF20 is predicted by 10% of titanium oxide and SPF10 is predicted by 5%, the prescription of 7% of titanium oxide is predicted by SPF14) In the case where the value of the in vivo SPF is known, the preliminary measurement can be omitted as necessary. In other words, the preliminary measurement is important for making a high degree of prediction, but may be omitted depending on various conditions such as shortening the processing time.

EXAMPLE

By way of examples, the present embodiment will be described in more detail. In addition, the following Example has shown the example which carried out the preliminary measurement.

Example 1

(Measuring conditions)

In the measuring apparatus shown in the above embodiment, the light source emitted from the xenon lamp light source transmits the WG320 filter and the UG11 filter (both manufactured by SCHOTT), respectively, to obtain a light source having a wavelength of 290 to 400 nm. As a skin replacement membrane, it arrange | positions so that it may become an irradiation distance of 1-2 mm from a light source using PMMA (methyl polymethacrylate) resin plate (Plexiglas ^™ , product of Schonberg GmbH & Co. KG). At this time, the intensity of UV-B is set to 2.0 MED / min. The coating amount of the sample onto the PMMA resin plate was 0.75 mg / cm ² , and the coating was applied by spreading a predetermined amount of sample with a finger on the surface of the PMMA resin plate for 1 minute. After application | coating, the sample was dried for 15 minutes on 25 degreeC conditions. In the preliminary measurement, light irradiation for 30 seconds is performed for 1 MED.

(Sample measurement)

Under the above measurement conditions, measurement was performed on Sample A whose in vivo SPF value was unknown. As a result of the preliminary measurement, the provisional in vitro SPF predicted value was 29.8, so the light irradiation time in this measurement was determined to be 29.8 × 0.5 = 14.9 minutes (14 minutes 54 seconds). In this measurement, continuous irradiation of this light irradiation time was performed. Moreover, the light irradiation time 14 minutes and 54 seconds was divided into five equal intervals, and the spectrum data of 6 points | pieces was acquired including the time of light irradiation start. About this spectrum data of 6 points, the time average spectrum was computed for every wavelength, and the final in vitro SPF prediction value (21.9) was obtained. This final in vitro SPF value was approximated to the in vivo SPF value (22.5) obtained later. Table 1 shows in vivo SPF values, and potential and final in vitro SPF estimates for Sample A.

Table 1

Example 2

About the measurement conditions, the measurement was performed about sample B whose in vivo SPF value is unknown on the conditions similar to Example 1. As a result of the preliminary measurement, the provisional in vitro SPF predicted value was 70.5, so the light irradiation time in this measurement was determined to be 70.5 x 0.5 = 35.25 minutes (35 minutes 15 seconds). In this measurement, continuous irradiation of this light irradiation time was performed. In addition, light irradiation time 35 minutes 15 seconds was divided into ten equal intervals, and the spectrum data of 11 points including the time of the start of light irradiation was acquired. About this spectrum of 11 points | pieces, the time average spectrum was computed for every wavelength, and the in vitro SPF prediction value 62.4 was obtained. This in vitro SPF estimate approximated the in vivo SPF value 64.5 obtained later. In vivo SPF values for sample B, and potential and final in vitro SPF estimates are shown in Table 1.

Example 3

About the measurement conditions, the sample C whose in vivo SPF value is unknown was measured on the same conditions as Example 1, and was measured. As a result of the preliminary measurement, the estimated in vitro SPF predicted value was 32.9, so the light irradiation time in this measurement was determined to be 32.9 × 0.5 = 16.25 minutes (16 minutes 15 seconds). In this measurement, continuous irradiation of this light irradiation time was performed. In addition, the light irradiation time of 16 minutes and 15 seconds was divided into five equal intervals, and spectral data of six points including the start of light irradiation were acquired. With respect to the spectral data of 11 points, a time average spectrum was calculated for each wavelength to obtain a final in vitro SPF predicted value of 32.2. This final in vitro SPF prediction approximated the in vivo SPF value of 31.5 obtained later. Table 1 shows in vivo SPF values, and potential and final in vitro SPF estimates for Sample C.

In Example 3, the provisional and final in vitro SPF estimates were approximated because the sample C was hardly affected by light deterioration due to continuous irradiation of light. The compounding component of Sample C is considered to be because the content of the organic ultraviolet absorbent which is susceptible to light deterioration is small and is mainly composed of inorganic titanium oxide or zinc oxide.

Comparative Example 1 to Comparative Example 3

The sample A, B, and C mentioned above were measured using the measurement conditions of Example 2 in patent document 1 which is a conventional method, and the in vitro SPF prediction value of each sample was obtained. Table 1 shows the in vitro SPF predictions of Samples A, B, and C obtained here.

Comparative Example 4 to Comparative Example 6

The sample A, B, and C mentioned above were measured using the method of the nonpatent literature 1 which is a conventional method, and the in vitro SPF prediction value of each sample was obtained. Table 1 shows the in vitro SPF predictions of Samples A, B, and C obtained here.

Referring to Table 1, in Examples 1 to 3, the final in vitro SPF predicted value according to the present evaluation method was very close to the in vivo SPF value obtained later. This result can be said to prove the validity of this evaluation method. Moreover, the final in vitro SPF prediction value by this evaluation method approximated by the in vivo SPF value rather than the in vitro SPF prediction value by the conventional evaluation methods disclosed by patent document 1 and the nonpatent literature 1. Therefore, this evaluation method can be said to be superior in the point which predicts in vivo SPF value from the conventional method.

According to this embodiment, the in vitro SPF predicted value reflecting the light deterioration phenomenon of the sample by the irradiation light and exhibiting a high correlation with the in vivo SPF value also in the sample exhibiting a high ultraviolet protective effect exceeding the SPF value of 50 or more. It is possible to obtain.

In addition, since the in vitro SPF predicted value obtained by the present measuring method has a very high correlation with the in vivo SPF value, the SPF value of the sample was simplified, rapid and highly accurate at the stage of the development of cosmetics having the effect of preventing sunburn. It can be measured by Therefore, since the development cost is low and a large number of samples can be evaluated in the development stage, the use of this evaluation method can further accelerate the development of cosmetics and the like having a high-performance sunburn prevention effect. have.

It is also applicable to the development and evaluation of nanomaterials and ultraviolet absorbers.

As mentioned above, although preferred embodiment and Example of this invention were described above, this invention is not limited to this specific embodiment, A various deformation | transformation and a change are within the range of the summary of this invention described in the claim. It is possible.

This international application claims the priority based on Japanese Patent Application No. 2006-274783 for which it applied on October 6, 2006, and uses all the content of 2006-274783 for this international application.

Claims (10)

A first step of measuring the change over time of the spectral transmission spectrum of the measurement sample by light irradiation of a light source including ultraviolet rays by a preset light irradiation time; A second step of performing correction according to the chronological change of the spectral transmission spectrum of the measurement sample based on the measurement result obtained by the first step; And a third step of calculating a final in vitro SPF prediction value of the measurement sample using the correction result obtained by the second step. The method of claim 1, The first step, A spectral transmission spectrum measurement step of measuring the spectral transmission spectrum of the measurement sample in a predetermined ultraviolet region at a predetermined wavelength interval; And an irradiation time setting step of setting a light irradiation time from the spectral transmission spectrum obtained by the spectral transmission spectrum measurement step. The method of claim 2, The irradiation time setting step, The correlation is calculated by multivariate regression analysis from the known in vivo SPF value of the standard sample and the spectral transmission spectrum of the standard sample, and the correlation is calculated. And calculating a provisional in vitro SPF prediction value of the measurement sample from the spectroscopic transmission spectrum of the measurement sample, wherein the provisional in vitro SPF prediction value is multiplied by 0.08 or more, and the provisional in vitro SPF prediction value is less than the time multiplied by 1.50. An evaluation method of the ultraviolet protective effect, characterized in that the light irradiation time. The method of claim 3, The multivariate regression method, A method for evaluating the ultraviolet protective effect, characterized by using PLS (Partial Least Squares) regression. The method of claim 1, The first step, Ultraviolet light characterized by controlling the light irradiation time in seconds with respect to the chronological change of the spectral transmission spectrum of the measurement sample, and acquiring data of the spectral transmission spectrum at any time during the light irradiation time. How to evaluate the protective effect. The method of claim 1, The first step, An evaluation method of the ultraviolet protective effect, characterized by measuring the change over time due to the light deterioration of the spectral transmission spectrum in the measurement sample. The method of claim 1, The second step, The method for evaluating the ultraviolet protective effect, characterized in that the time-dependent spectrum correction of the spectral transmission spectrum measured in the first step is corrected. The method of claim 3, The third step, And evaluating the final in vitro SPF predicted value from the correlation calculated in the irradiation time setting step and the time average spectrum corrected in the third step. The method of claim 2, The spectral transmission spectrum measurement step, And evaluating the ultraviolet rays to the skin substitute membrane through which the measurement sample is applied, and measuring the spectrum of the ultraviolet rays transmitted through the measurement sample and the skin substitute membrane. Time-varying measurement means for measuring the time-dependent change in the spectral transmission spectrum of the measurement sample by light irradiation of a light source including ultraviolet rays by a preset light irradiation time; Correction means for performing correction according to the chronological change of the spectral transmission spectrum of the measurement sample based on the measurement result obtained by the measurement means; And an SPF prediction value calculating means for calculating a final in vitro prediction value of the measurement sample using the correction result obtained by the correction means.

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